1. Field of the Invention
The present invention relates to electrical stringed instruments and signal processing circuits therefor, and, more particularly, to a system and method for producing an output from an electrical stringed musical instrument that detects and converts certain frequencies on the electrical stringed musical instrument.
2. Description of the Related Art
Conventional stringed instruments have a limited audio range. For example, the conventional six string guitar has a limited tonal spectrum and is able to achieve sounds above the lowest open string (when tuned at standard “A 440 Hz” the lowest open string, “E”), which vibrates at 82.41 Hz when plucked.
In the case of conventional guitars, while there is typically some overlap in the audio ranges of a lead guitar and a bass guitar, the lead guitar cannot produce the range that the bass guitar can produce. Consequently, it is common for many types of bands or musical groups to include a musician who plays lead guitar, and a second musician who plays bass guitar.
An alternative would be to provide a guitar with the six strings used for a lead guitar, and additional low end strings that would extend the range of the guitar into the range of a bass guitar. This would allow one musician to play bass and lead on the same guitar. However, it would be difficult, if not impossible, for such a guitar to produce the sound that can be produced by conventional lead and bass guitars played by different musicians. This type of guitar would also be extremely difficult to play, due to the presence of more than six independent strings.
Another alternative, represented by U.S. Pat. No. 4,481,854, is to suppress certain frequencies produced by the strings of a lead guitar in an attempt to selectively lower the range of the strings. This does not, however, produce true bass, in that the range of the sound produced by the strings is not actually shifted into a new range.
U.S. Pat. No. 8,502,061 (“the '061 patent”), entitled “Electrical Stringed Instrument and Signal Processing Circuit Therefor” and invented and owned by the inventor of the present application (the disclosure of which is incorporated herein by reference), describes a methodology for extending the range of an electrical stringed musical instrument (e.g., a conventional lead guitar). More specifically, the methodology of the '061 patent employs first and second pickup circuits, wherein the first pickup circuit is associated with a first set of the strings of the instrument (e.g., all of the strings) and the second pickup circuit is associated with only a subset of the strings of the instrument (e.g., the low E and A strings). According to the methodology, the first pickup circuit is structured to produce a first electrical signal corresponding to a first audio range in response to vibration of one or more of the strings in the subset, and similarly the second pickup circuit is structured to produce a second electrical signal corresponding to the first audio range in response to vibration of the one or more of the strings in the subset. However, also according to the methodology, the second electrical signal is converted into a third electrical signal corresponding to a second audio range different than the first audio range (e.g., one octave lower) using a signal processor of the second pickup circuit. As a result, a user of the instrument is able to produce sounds in both the first audio range and the second audio range using the subset of strings, and may do so simultaneously. Thus, in the case where the instrument is a conventional (lead) guitar, the user may generate conventional lead guitar sounds and bass guitar sounds by strumming the subset of strings, and may do so simultaneously.
Furthermore, in the methodology described in the '061 patent, if multiple strings from the subset of strings (e.g., all of the strings in the subset) are played at the same time, the signal from each of those strings will be converted to the lower audio range and multiple bass notes will be resounded. This will often result in an undesirable muddy or muddled sound. This application addresses this issue with a variety of solutions.